The present invention relates to a piezoelectric thin-film element formed with niobate lithium potassium sodium thin-film having a well-developed Perovskite structure having an excellent piezoelectric characteristic.
A piezoelectric component is formed into various kinds of piezoelectric elements according to various purposes, and generally used as functional electronic part such as actuators for generating a displacement in response to the applied voltage and sensors for generating a voltage in response to the mechanical displacement of the element.
As for the piezoelectric component used for the actuators and sensors, ferroelectric substance composed of lead-based materials having an excellent piezoelectric characteristic, especially erovskite-type ferroelectric substances based on Pb(Zr1-xTix)O3, called PZT, are generally used. This piezoelectric component is typically formed by sintering the oxide composed of individual elements.
As various electronic parts are made down-sized and sophisticated today, down-sizing and sophistication of the piezoelectric component is also required. In the piezoelectric materials formed by the conventional process mainly including a sintering method, however, in attempting to make the thickness of the material smaller especially near 100 μm, the thickness becomes the dimension equivalent to the size of the crystal grains forming the material, and thus, the effect due to this dimensional condition may not be negligible, which leads to such a problem that the dispersion and degradation in the characteristics becomes distinguished.
In order to solve above described problem, the recent research effort is directed to a method for forming piezoelectric components by applying thin-film technologies in stead of sintering method (see Japanese Patent Laid-Open Number 2002-151754). As an example, PZT thin-films formed by RF spattering method are recently developed and practically applied to a head actuator for high-definition and high-speed ink jet printers.